CN104211146A - Method for inhibiting blue algae from growth by using plant fallen leaves - Google Patents

Abstract

The invention discloses a method for inhibiting the growth of cyanobacteria by using fallen leaves of plants. The method for inhibiting the growth of cyanobacteria is to put the leachate of fallen leaves of plants into a fresh water system containing cyanobacteria. The allelochemicals contained in the leachate of fallen leaves of plants can effectively inhibit the growth of cyanobacteria. So as to achieve the purpose of controlling the excessive growth of cyanobacteria. The method for inhibiting the growth of cyanobacteria by using fallen leaves of plants in the present invention is simple, easy to operate, and low in treatment cost, and realizes the control of excessive reproduction of typical algae in freshwater water systems, ensures the safety of the freshwater water system environment, and has the advantages of controlling cyanobacteria blooms. Broad application prospects.

Description

A method for inhibiting the growth of cyanobacteria by using plant defoliation

technical field

The invention relates to the technical field of algae control, in particular to a method for inhibiting the growth of cyanobacteria by using fallen leaves of plants.

Background technique

Since the last century, due to the increasing economic activities of human beings, various domestic sewage and urban wastewater have been discharged into rivers, lakes and seas, causing the water body to absorb too much nutrients such as nitrogen and phosphorus and become eutrophic, resulting in frequent occurrence of "water blooms". It has become one of the most serious environmental disasters in the world today, and it often occurs in various lakes, rivers and sea areas in our country. Algal blooms can deplete dissolved oxygen in water bodies, suffocate aquatic animals and bring losses to aquaculture. Many algae can produce algal toxins, which can poison various animals or pass through the food chain, threatening human health.

Microcystis aeruginosa is the most harmful cyanobacteria that can cause algae blooms in freshwater bodies, and its control and suppression have always been a hot topic of research by scientists. At present, there are three main types of algae suppression technology in the lake: physical method, chemical method and microbial method. However, the physical method is costly and uneconomical, and cannot fundamentally solve the stimulating effect of nutrients on algae; although the chemical method of algae removal has a certain effect, the time effect is relatively fast, and it can quickly kill algae, but the secondary damage caused by dead algae Pollution and the bioaccumulation and amplification of chemicals have a greater negative impact on the entire ecosystem. Long-term use of low-concentration chemicals will cause algae to develop resistance, which may easily cause environmental pollution or destroy ecological balance, and there may be long-term harm; Although microbial technology has many advantages in algae removal, the infectivity, effectiveness and adaptability of the virus under natural conditions have yet to be studied. There are also sensitive groups and resistant groups in the host algae of the virus. Then become the obstacle of its specific algae killing. These disadvantages thus limit their generalization.

Allelopathic algae removal is a recent development of biological algae removal technology. The direct or indirect effect of a plant on another organism by releasing chemical substances into the environment. The released chemical substances are allelochemicals. Allelochemicals are metabolites of plants, which are easy to degrade in water bodies and have limited pollution to water bodies; and plants come from a wide range of sources, and different allelochemicals can be obtained from different plants; the effective dose of allelochemicals for algae removal is micrograms/L or less , with high efficiency; allelochemicals are generally algae-inhibiting, non-algicidal reagents, do not destroy algae cells, and the contents of cells do not enter the water body, and the sludge output is small, which is beneficial to subsequent treatment. Therefore, based on the above reasons, it is of great significance to apply allelochemicals to inhibit the growth of cyanobacteria such as Microcystis aeruginosa and protect the ecological environment.

Contents of the invention

In view of the deficiencies in the prior art above, the object of the present invention is to provide a method for inhibiting the growth of cyanobacteria by using fallen leaves of plants, aiming to solve the problems of high cost, secondary pollution, specificity, effectiveness, Ecological problems.

In order to achieve the above object, the present invention has taken the following technical solutions:

A method for suppressing the growth of blue-green algae by using plant defoliation, comprising the steps of:

A, the cyanobacteria that will be in logarithmic growth phase are inoculated in BG-11 medium;

B. Then add plant fallen leaves leachate, and place in light incubator to cultivate by alternating light and dark culture, and inhibit the growth of cyanobacteria by plant fallen leaves.

The method for inhibiting the growth of cyanobacteria by using fallen leaves of plants, wherein the BG-11 medium is prepared from the following components: NaNO ₃ 1.5g, K ₂ HPO ₄ 0.04g, MgSO ₄ ·7H ₂ O 0.075g , CaCl ₂ ·7H ₂ O 0.036g, Na ₂ CO ₃ 0.02g, citric acid 0.006g, ferric citrate 0.006g, trace element solution 1mL, distilled water to 1000 mL.

The method for inhibiting the growth of cyanobacteria by using fallen leaves of plants, wherein, when cultivating in a light incubator, the light-to-dark ratio is 12h:12h.

The method for inhibiting the growth of blue-green algae by utilizing plant defoliation, wherein the plant defoliation is human face defoliation.

The method for inhibiting the growth of blue-green algae by using fallen leaves of plants, wherein the leachate of fallen leaves of plants is 2.0 g·L ^-1 .

The method for inhibiting the growth of cyanobacteria by using fallen leaves of plants, wherein, the cultivation temperature in the step B is 26°C.

The method for using fallen leaves of plants to inhibit the growth of cyanobacteria, wherein the leaf extract of fallen leaves of plants is prepared according to the following steps:

S1. Collect the fallen leaves of plants, rinse them with water, dry them, cut them into small sections and crush them into leaves for later use;

S2. Take the crushed leaves and soak them in distilled water, seal them with a parafilm and place them in an artificial climate box, place them in a dark environment for a period of time, and filter them through a microporous membrane under reduced pressure to obtain plant leaf extracts.

The method for inhibiting the growth of cyanobacteria by using fallen leaves of plants, wherein the trace element solution is prepared from the following components: 0.286g H ₃ BO ₄ , 0.181g MnCl ₂ ·4H ₂ O, 0.0222g ZnSO ₄ , 0.039g Na ₂ MoO ₄ , 0.0079g CuSO ₄ ·5H ₂ O, 0.00494g Co(NO ₃ ) ₂ ·6H ₂ O, distilled water to 100 mL.

The method for inhibiting the growth of cyanobacteria by using fallen leaves of plants, wherein, in the step B, the light intensity is 30 μmol·m ^-2 ·s ^-1 .

The method for inhibiting the growth of cyanobacteria by using plant defoliation, wherein, in the step A, after inoculation, the initial density of cyanobacteria is 10 ⁵ cell·mL ^-1 .

A method for inhibiting the growth of cyanobacteria by using plant fallen leaves of the present invention, by using plant fallen leaves as raw materials to prepare plant fallen leaf leaching liquid, and putting the plant fallen leaf leaching liquid into the cyanobacteria medium to be treated, so as to inhibit the growth of cyanobacteria in the medium to be treated .

After adopting the above scheme of the present invention, the present invention has the following advantages compared with the prior art:

1. Microcystis aeruginosa is a common cyanobacteria species that occurs in water blooms. It has been proved by experiments that the plant leaf leaching solution has a significant inhibitory effect on its growth and has more practical application value.

2. The collection and preparation process of plant fallen leaf extract is simple, and the required equipment is conventional equipment, which is suitable for the application of different water plants at home and abroad.

3. Using the allelochemicals contained in the leaf extract, the culture time reached 15 days. Compared with the control group, the cyanobacteria basically could not grow normally, and had a strong algae inhibitory effect.

4. The allelochemicals in leaf leaching solution had a strong inhibitory effect on the growth of cyanobacteria. Based on the dry weight of fallen leaves, when the concentration of leaf leaching solution was 2.0 g·L ^-1 , it could inhibit 100 mL of algae liquid, and the algae inhibition effect was obvious.

5. Using the fallen leaves of human face to inhibit the growth of cyanobacteria has the characteristics of reusing waste. the

6. Compared with other methods of chemically inhibiting the growth of algae, only a very low concentration of leaf extract is needed, and the treatment method is simple and the operation process is simple. the

7. The invention does not need to input other chemical reagents, saves the input cost of other chemical reagents, and reduces the problems of increased sludge volume and increased treatment capacity caused by the addition of other chemical reagents.

Detailed ways

The present invention provides a method for inhibiting the growth of cyanobacteria by using fallen leaves of plants. In order to make the purpose, technical scheme and effect of the present invention clearer and clearer, the present invention will be further described in detail below. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The invention provides a method for inhibiting the growth of cyanobacteria by using plant fallen leaves. The method for inhibiting the growth of cyanobacteria is to put the plant fallen leaf leachate into the culture medium containing cyanobacteria, and some allelochemical substances contained in the plant leaf leachate, the allelochemical Can effectively inhibit the growth of blue-green algae, so as to achieve the purpose of inhibiting the growth of blue-green algae.

A method for suppressing the growth of blue-green algae by using plant defoliation, comprising the steps of:

A, the cyanobacteria that will be in logarithmic growth phase are inoculated in BG-11 medium;

B. Then add plant fallen leaves leachate, and place in light incubator to cultivate by alternating light and dark culture, and inhibit the growth of cyanobacteria by plant fallen leaves.

In the present invention, the BG-11 medium is prepared from the following components: NaNO ₃ 1.5g, K ₂ HPO ₄ 0.04g, MgSO ₄ ·7H ₂ O 0.075g, CaCl ₂ ·7H ₂ O 0.036g, Na ₂ CO ₃ 0.02g, citric acid 0.006g, ferric citrate 0.006g, trace element solution 1mL, distilled water to 1000mL. In the medium prepared by this formula, cyanobacteria can be in a good growth state.

Preferably, when the present invention is cultivated in a light incubator, the light-to-dark ratio is 12h:12h. The light cycle is an important factor affecting the growth of cyanobacteria, and it is not conducive to the growth of cyanobacteria in the absence of light or 24 hours of light. In the present invention, the growth rate of cyanobacteria is the fastest under the light-dark ratio of 12h:12h.

In the present invention, the fallen leaves of the plant are preferably the fallen leaves of renmin, and the renmin is a large tree plant of Anacardiaceae. The growth of cyanobacteria can be effectively inhibited by using the leaching solution of fallen leaves of Renmianzi. Not only can the growth of cyanobacteria be inhibited by only inputting a very low concentration of leaching solution of fallen leaves, but also no need to input other chemical reagents, thus avoiding the amount of sludge caused by adding other chemical reagents increase and increase in throughput.

Further, when the concentration of the plant leaf extract added in step B of the present invention is 2.0 g·L ^-1 , the inhibitory effect is optimal. It can be seen that the present invention can obviously inhibit the growth of cyanobacteria only by adding a very low concentration of plant leaf extract, which is because the allelochemicals contained in the plant leaf extract have a strong inhibitory effect on the growth of cyanobacteria.

Further, the cultivation temperature in Step B of the present invention is 26° C., because this temperature is more conducive to the growth of cyanobacteria.

Among the present invention, the cultivation time reaches 15d in step B, and this is because along with the prolongation of cultivation time, it is beneficial to compare the algae control effect of the treatment group to the cyanobacteria, the growth of the cyanobacteria in the control group has reached the logarithmic growth phase, and the treatment group Cyanobacteria growth was well controlled.

Among the present invention, described plant fallen leaves leachate is prepared according to the following steps:

S100, collecting the fallen leaves of the plants, washing them with water, drying them, cutting them into small sections and crushing them into leaves for later use;

S200, taking the crushed leaves and soaking them in distilled water, sealing them with a parafilm and placing them in an artificial climate box, placing them in a dark environment for a period of time, and filtering them through a microporous membrane under reduced pressure to obtain plant leaf extracts.

Further, the trace element solution described in the present invention is prepared from the following components: 0.286g H ₃ BO ₄ , 0.181g MnCl ₂ ·4H ₂ O, 0.0222g ZnSO ₄ , 0.039g Na ₂ MoO ₄ , 0.0079 g CuSO ₄ ·5H ₂ O, 0.00494g Co(NO ₃ ) ₂ ·6H ₂ O, distilled water to 100 mL.

In step A of the present invention, after inoculation, the initial density of cyanobacteria is about 10 ⁵ cell·mL ^-1 . The initial density of cyanobacteria also has a certain influence on the growth of algae. An appropriate amount of cyanobacteria in the medium is more conducive to the growth of cyanobacteria. When the initial density of cyanobacteria is too large, the nutrients in the medium are limited, thereby inhibiting the growth of cyanobacteria. Therefore, according to the experimental research of the present invention, the growth of cyanobacteria is best when the initial density of cyanobacteria is about 10 ⁵ cell·mL ^-1 .

Further, in step B of the present invention, the light intensity is about 30 μmol·m ^-2 · s ^-1 . Light is an important factor for the growth of cyanobacteria. Different light intensities have obvious differences on the growth of cyanobacteria. In a certain light range, the rate of photosynthesis increases with the increase of light. If the light is too strong, the photosynthetic organs may be destroyed, and the growth of cyanobacteria will be inhibited. After studying the influence of different light intensities on the growth of cyanobacteria, the present invention finds that the optimum light intensity for the growth and photosynthesis of cyanobacteria is about 30 μmol·m ^{- 2} · s ^-1 , so as to ensure that the cyanobacteria are in the best growth state.

The present invention will be further described below in conjunction with examples. The preparation method of the plant leaf extract in the following examples is as follows: collect the plant leaves (specifically, the fallen leaves of human face), rinse them with tap water, and then dry them at 40°C for 4 days until the leaves become brittle and easy to crush. Then cut it into 2cm pieces, and crush it into leaves about 0.1cm long for later use; take 50g of the crushed leaves and soak them in a 1L Erlenmeyer flask filled with 500mL distilled water, seal them with a sealing film and place them at 26±1℃ artificially. In a constant temperature climate box, place it in a dark environment for 4 days, take the soaked leaf leachate, filter it through a microporous membrane with a pore size of 0.22 μm under reduced pressure, and remove the filter residue to reduce the influence of other microorganisms. The filtered leachate is placed in Store in a refrigerator at 4°C to obtain the extract of the fallen leaves of Renmianzi, the concentration of which is 0.1 g·mL ^-1 , and the color is reddish brown.

In each embodiment of the present invention, the Microcystis aeruginosa liquid inoculated into the culture medium is in the logarithmic growth phase, which is the Microcystis aeruginosa liquid obtained from about 15 days after the inoculation, and the color is dark green.

The Microcystis aeruginosa described in the present invention was purchased from the Freshwater Algae Species Bank (FACHB) of the Type Culture Collection Committee of the Chinese Academy of Sciences.

Microcystis aeruginosa relies on photosynthesis to grow, and chlorophyll a is the main photosynthetic pigment of Microcystis aeruginosa, which can be used as an indicator to measure the potential of photosynthesis. As the pigment of living algal cells, the change of the concentration of chlorophyll a also reflects the change of the growth of Microcystis aeruginosa in the water system.

Example 1

Add 100mL of BG-11 to two 250mL Erlenmeyer flasks and mark them as No. 1 and No. 2. Inoculate 1 mL of Microcystis aeruginosa liquid in the late logarithmic growth stage into an Erlenmeyer flask filled with 100 mL of BG-11 medium. After inoculation, the initial density of Microcystis aeruginosa is about 10 ⁵ cell·mL ^-1 . No. 1 was used as the control group; No. 2 was used as the treatment group. The prepared extract of fallen leaves of Renmianzi was added to the culture medium. After adding, the concentration of the extract of fallen leaves of Renmianzi (working concentration in the whole system) was 2.0 g·L ^-1 . The Erlenmeyer flask was cultured in a light incubator with a light intensity of about 30 μmol m ^-2 s ^-1 , a light-to-dark ratio of 12h:12h, a temperature of 26°C, manual shaking twice a day, and a culture time of 15d. The chlorophyll-a concentration of Microcystis aeruginosa was determined by phytoplankton fluorescence classifier equipment (PHOTO-PAM, WLAZ Company, Germany). Three parallel samples were set up in the control group and the treatment group respectively, and the experiment was repeated three times.

The results showed that on the 1st day, no matter in the control group or the treatment group, the chlorophyll a was about 30 μg·L ^-1 , and the difference was not significant; on the 15th day, in the control group No. 1, Microcystis aeruginosa grew normally , its chlorophyll a concentration is: 4503.75μg·L ^-1 ; while in No. 2 treatment group, Microcystis aeruginosa grows very slowly, almost stagnant growth, its chlorophyll a concentration is: 18.66μg·L ^-1 , visible aeruginosa The growth of Microcystis was severely inhibited, that is, the allelochemicals released from the leaching solution of fallen leaves of Renmianzi could obviously control the growth of Microcystis aeruginosa.

Example 2

Add 100 mL of BG-11 to five 250 mL Erlenmeyer flasks and mark them as No. a, No. b, No. c, No. d, No. e and No. f. Inoculate 1 mL of Microcystis aeruginosa liquid in the logarithmic growth phase into an Erlenmeyer flask filled with 100 mL of BG-11 medium. After inoculation, the initial density of Microcystis aeruginosa is about 10 ⁵ cell·mL ^{- 1} . Add the prepared extract of fallen leaves of Renmianzi to the medium. After adding, the concentrations of the extract of fallen leaves of Renmianzi in No. a, No. b, No. c, No. d, No. e and No. f Erlenmeyer flasks are 0.0 g·L ^{- 1} , 0.4 g·L ^-1 , 0.8 g·L ^-1 , 1.2 g·L ^-1 , 1.6 g·L ^-1 , 2.0 g·L ^-1 . The Erlenmeyer flask was cultured in a light incubator, the light intensity was about 30 μmol m ^-2 s ^-1 , the light-dark ratio was 12h:12h, the temperature was 26°C, manual shaking was done twice a day, and the culture time was 15 d. The chlorophyll-a concentration of the algae was measured using a phytoplankton fluorescence classifier. Three parallel samples were set up for each group, and the experiment was repeated 3 times.

The results showed that the growth of Microcystis aeruginosa in group a with a concentration of 0.0 g·L ^-1 in the extract from fallen leaves of Renmianzi was normal. On the 15th day, the concentration of chlorophyll a was: 4503.71 μg·L ^-1 ; the concentration was 0.4 g·L The growth rate of Microcystis aeruginosa in group b of ^-1 was not as fast as that of group a, and the growth of Microcystis aeruginosa was inhibited to some extent. On the 15th day, the concentration of chlorophyll a was: 2648.71 μg·L ^-1 ; the concentration was 0.8 The growth rate of Microcystis aeruginosa in group c of g·L ^-1 was not as fast as that in group b, and the growth of Microcystis aeruginosa was more inhibited. The concentration of chlorophyll a on the 15th day was 172.48 μg·L ^-1 ; the concentration was The growth rate of Microcystis aeruginosa in group d with 1.2 g L ^-1 was not as fast as that in group c, and the growth of Microcystis aeruginosa was more significantly inhibited. On the 15th day, the concentration of chlorophyll a was: 101.51 μg·L ^-1 ; the growth rate of Microcystis aeruginosa in group e with a concentration of 1.6 g·L ^-1 was not as fast as that in group d, and the growth of Microcystis aeruginosa was more obviously inhibited. On the 15th day, the concentration of chlorophyll a was : 40.07 μg·L ^-1 ; group f with a concentration of 2.0 g·L ^-1 had the slowest growth rate of Microcystis aeruginosa, and the growth of Microcystis aeruginosa almost stagnated. On the 15th day, its chlorophyll a concentration was: 19.48μg· L ^-1 . It can be seen that when the concentration of the extract from fallen leaves of Renmianzi is 2.0 g·L ^-1 , the extract from fallen leaves of Renmianzi has the best inhibitory effect on the growth of Microcystis aeruginosa.

Example 3

Add 100 mL of BG-11 to culture-based two 250 mL Erlenmeyer flasks and mark them as A1 and A2. Inoculate 1 mL of Microcystis aeruginosa liquid in the late logarithmic growth stage into an Erlenmeyer flask filled with 100 mL of BG-11 medium. After inoculation, the initial density of Microcystis aeruginosa is about 10 ⁵ cell·mL ^{- 1} . A1 was used as the control group, and A2 was used as the treatment group. The prepared extract from the fallen leaves of N. chinensis was added to the culture medium. After the addition, the concentration of the extract from the fallen leaves of N. chinensis was 2.0 g·L ^-1 . The Erlenmeyer flask was cultured in a light incubator with a light intensity of 30 μmol·m ^-2 · s ^-1 , a light-to-dark ratio of 12h:12h, a temperature of 26°C, and manual shaking twice a day. The A1 control group and the A2 treatment group were sampled on the 1st, 4th, 7th, 10th and 15th day, respectively, and the concentration of algae chlorophyll a was measured using the phytoplankton fluorescence classifier equipment. Three parallel samples were set up for each group, and the experiment was repeated 3 times.

The results showed that with the prolongation of culture time, the chlorophyll a of Microcystis aeruginosa in the A1 control group showed a significant upward trend, the growth of Microcystis aeruginosa was normal, and the chlorophyll a of the 1st, 4th, 7th, 10th and 15th day were respectively : 30.92 μg·L ^-1 , 854.91 μg·L ^-1 , 2184.75 μg·L ^-1 , 3083.95 μg·L ^-1 , 4601.82 μg·L ^-1 ; the chlorophyll a of Microcystis aeruginosa decreased significantly in the A2 treatment group The growth of Microcystis aeruginosa was inhibited to varying degrees. The growth of Microcystis aeruginosa showed a downward trend between the 1st and 4th day, and its chlorophyll a was about 30.83 μg·L ^-1 and 28.53 μg·L ^-1 , and the growth of Microcystis aeruginosa still showed a significant decline on the 7th day chlorophyll a was about 24.36 μg·L ^-1 , the chlorophyll a of Microcystis aeruginosa was about 21.94 μg·L ^-1 on the 10th day, and the chlorophyll a of Microcystis aeruginosa was about 17.86 μg·L ^-1 on the 15th day ¹ . It can be seen that when the culture time is 15 days, the leaching solution of fallen leaves of Renmianzi has the best effect on inhibiting the growth of Microcystis aeruginosa.

It can be seen from the above examples that the leaf extract of plants can effectively inhibit the growth of Microcystis aeruginosa, thereby achieving the purpose of inhibiting the growth of Microcystis aeruginosa. And in practical application, using the allelochemical substances contained in plant leaf extracts to control algae does not need to add any other chemical reagents, and strongly inhibits the growth of Microcystis, which has broad application prospects for controlling cyanobacteria blooms.

It can be understood that those skilled in the art can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention, and all these changes or replacements should belong to the protection scope of the appended claims of the present invention.

Claims (10)

1. utilize plant defoliation to suppress a method for blue algae growth, it is characterized in that, comprise step:

A, the blue-green algae being in logarithmic phase is inoculated in BG-11 substratum;

B, then add plant defoliation leach liquor, and be placed in illumination box and cultivate over-over mode by illumination and cultivate, suppressed the growth of blue-green algae by plant defoliation.

2. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, is characterized in that, described BG-11 substratum, formulated by following component: NaNO ₃1.5g, K ₂hPO ₄0.04g, MgSO ₄7H ₂o 0.075g, CaCl ₂7H ₂o 0.036g, Na ₂cO ₃0.02g, citric acid 0.006g, ironic citrate 0.006g, trace element solution 1mL, distilled water is settled to 1000 mL.

3. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, it is characterized in that, when cultivating in illumination box, Light To Dark Ratio is 12h:12h.

4. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, is characterized in that, described plant defoliation is Fruit of Indochina Gragonplum fallen leaves.

5. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, it is characterized in that, described plant defoliation leach liquor is 2.0gL ^-1.

6. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, it is characterized in that, in described step B, culture temperature is 26 DEG C.

7. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, it is characterized in that, described plant defoliation leach liquor is prepared according to the following steps:

S1, collect plant defoliation, rinse well with water, then dry, be cut into segment and rubbed that to be broken into blade for subsequent use;

S2, get and rub broken blade and be soaked in distilled water, sealed membrane sealing is placed in growth cabinet, places for some time, and through millipore filtration filtration under diminished pressure, obtain plant defoliation leach liquor under dark surrounds.

8. the method utilizing plant defoliation to suppress blue algae growth according to claim 2, is characterized in that, described trace element solution, formulated by following component: to get 0. 286g H ₃bO ₄, 0.181g MnCl ₂4H ₂o, 0.0222g ZnSO ₄, 0.039g Na ₂moO ₄, 0.0079g CuSO ₄5H ₂o, 0.00494g Co (NO ₃) ₂6H ₂o, distilled water is settled to 100 mL.

9. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, it is characterized in that, in described step B, intensity of illumination is 30 μm of ol m ^-2s ^-1.

10. the method utilizing plant defoliation to suppress blue algae growth according to claim 1, it is characterized in that, in described steps A, after inoculation, the initial density of blue-green algae is 10 ⁵cellmL ^-1.